Doesn’t it feel like there are only ever terrible things reported in the news media? Let me rephrase that: When is the world ever presented as NOT a dumpster fire – except this fire can’t even keep us warm so we’ll all die freezing cold when the White Walkers come? Escalating tensions with North Korea and/or Russia (actually, by the time I’ve gotten around to posting this, relations on the Korean peninsula have significantly improved – go figure), a global surge in xenophobia and nationalism, a full half of Taylor Swift’s new singles are garbage. It’s bleak. My personal media drip has a hearty helping of environmental news, and boy howdy it is no better on that front.
But lo, I’ve found a ray of sunshine. This study found that the lionfish population in part of the Bahamas is decreasing – and that’s a good thing (I’ll explain). Now everything else doesn’t seem so bad! If we’re going down at least we’ll take those spiky, punk bastards with us, right? Ok, ok, maybe it’s not a huge win. Maybe it barely registers on most folks’ scorecards, but it’s something and I’ll take it.
Quick! To the background-mobile!
Lionfish (Pterois volitans and Pterois miles for nerds) are the marine invasive posterchildren of the 21st century. First spotted off the coast of Florida in 1985, they didn’t move into the Caribbean proper until the early 2000s. Native to the Indian Ocean where they’re pretty much just whatever, in the Caribbean and Atlantic they’re 13-15 TIMES more abundant, and they seriously jack things up. They eat everything, nothing eats them, and they hump like rabbits… errr… spawn… like… … ocean rabbits. Basically, the problem is that there are a ton of them, and they prey on the young of native fish species, exacerbating population declines already occurring due to habitat destruction, commercial overfishing, ocean warming, and the rest of the mammoth list of issues that I don’t have the emotional fortitude (and you don’t have the attention span) to get into here.
Snap back to our ray of sunshine.
The short and sweet of the above-linked study is as follows: lionfish abundance increased from 2005-2009, leveled off 2010-2011, and then decreased significantly between 2011 and 2015 (when the study ended). Note that I’m using the scientific definition of “significantly.” I’m not saying the decrease in lionfish was huge (it wasn’t), I’m saying the authors are confident the decline really happened and wasn’t 1) a fluke, 2) an error, or 3) some grand illusion perpetrated by Bahamian mermaids relocating lionfish to fool the scientists. No, this decline happened. The issue is that we have no clue why. The authors discussed several possible explanations of varying plausibility, but what really got me all a-quiver was that – no matter the ultimate cause – this decline appears to be natural. As in, not human-caused. We did absolutely nothing about the invading lionfish situation and the problem just started going away on its own. Isn’t that the dream? Usually, we double down and introduce another invasive species to eat the first one, leading to cartoonishly disastrous results like when we introduced the cane toad to Australia to control sugar cane-destroying beetles and it ate everything BUT those beetles, with the added bonus of killing people’s dogs.
Sometimes we cut out the middle man (animal…manimal?) and take the killing and eating into our own prehensile hands. Lionfish are absolutely edible – delicious even, by some accounts – once you remove their venomous spines (as per the video below). Numerous advocacy groups and restaurants are attempting to create a consumer demand for lionfish, and you can see here where in the Caribbean and US you can get some for yourself. If enough people want to eat them, you better believe that fishermen will get out there and catch every last one.
While lionfish aren’t flying off plates quite yet, people are still killin’ ‘em just the same. Many professional scuba divers taking customers out diving will bring a speargun for any lionfish they come across (I personally watched a dive-guide spear a lionfish and feed it to an eel; it was rad). On the Caribbean island of Bonaire, they have a lionfish-hunting legion – 300 divers specifically trained and licensed to spear the invaders (spearfishing is otherwise illegal there). Their war on the voracious pests has been lethally effective: lionfish numbers are almost 3x lower on parts of the island where the spearfishers operate vs. where there is no spearfishing. And when you compare Bonaire to neighboring Curaçao where lionfish removal was begun two years later? There are more than 4x as many lionfish on Curaçao compared to the areas of Bonaire where the spearfishers are doing their thing. (Quick note: this study tallied the amount of lionfish in an area as biomass [weight], not the number of individual fish. Biomass is a beneficial way to approach a question like: “Are there fewer lionfish at this location as opposed to that location over there?” because the sizes of individuals can vary greatly.)
So this is awesome; we can actually eliminate these things fast enough to make a dent in the population, which the study authors prove with math (or, more specifically, math from other studies – see their references). How long until they’ve hunted these things to local extinction on Bonaire then? Eeeeehhhh that might not happen because 1) baby lionfish from other islands can be brought to Bonaire by currents, 2) divers can’t reach down deep (>40m or 130ft) where the large (and fecund) lionfish live, and 3) divers can’t easily access the windward (eastern) side of the island so there’s hardly any fishing there.
I’d like you to recall the first study I discussed in which lionfish populations were found to be naturally decreasing in the Bahamas. That’s where the lightbulb goes off, at least it did for me. See, what if, through a combination of good, old-fashioned human nature-killin’ and the even more classic we-have-no-idea-maybe-spirits-or-like-physics-we-guess (aka natural declines) we could eliminate lionfish in the Caribbean? That’d be pretty sweet.
I want to be very clear that, even though I said lionfish were naturally declining in the Bahamas, that in NO WAY MEANS that we should stop trying to do something about the problem. In fact, the study authors point out that the declines are probably nothing to do with the lionfish specifically, given that other species they monitored during the same period declined as well. This is indicative of factors operating on large scales to impact how many baby fish – of all species – are surviving year-to-year, things like hurricanes, water temperatures, and ocean currents.
The bigger take-away, in my opinion, is that lionfish aren’t immune to these kinds of factors, as their explosive population increase seemed to indicate before. If we start eating them, native fish start eating them (which there’s some evidence they may start to do), and we continue with programs like Bonaire’s lionfish removal, there’s a chance that we can get them under control.
Some folks are getting even more creative. In Belize, where there’s already decent demand among local restaurants for some tasty, tasty invader, women are creating some hardcore beautiful jewelry out of lionfish spines. Then there’s this absolute legend of a bad*ss spearing lionfish and hand-feeding them to sharks with the aim of teaching them to hunt for lionfish on their own. It’s kind of like trying to get kindergarteners to eat vegetables at snack time. I’m saying this guy is a kindergarten teacher for sharks. What’s on your resume?
Johnny Venger can’t get his sharks to learn anything.
References:
Benkwitt CE, Albins MA, Buch KL, Ingeman KE, Kindinger TL, Pusack TJ, Stallings CD, Hixon MA (2017) Is the lionfish invasion waning? Evidence from The Bahamas. Coral Reefs 36:1255–1261
de León R, Vane K, Bertuol P, Chamberland V, Simal F, Imms E, Vermeij M (2013) Effectiveness of lionfish removal efforts in the southern Caribbean. Endanger Species Res 22:175–182
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